Showing papers on "Anticipation (genetics) published in 2011"

Genetic anticipation is associated with telomere shortening in hereditary breast cancer.

Abstract: There is increasing evidence suggesting that short telomeres and subsequent genomic instability contribute to malignant transformation. Telomere shortening has been described as a mechanism to explain genetic anticipation in dyskeratosis congenita and Li-Fraumeni syndrome. Since genetic anticipation has been observed in familial breast cancer, we aimed to study telomere length in familial breast cancer patients and hypothesized that genetic defects causing this disease would affect telomere maintenance resulting in shortened telomeres. Here, we first investigated age anticipation in mother-daughter pairs with breast cancer in 623 breast cancer families, classified as BRCA1, BRCA2, and BRCAX. Moreover, we analyzed telomere length in DNA from peripheral blood leukocytes by quantitative PCR in a set of 198 hereditary breast cancer patients, and compared them with 267 control samples and 71 sporadic breast cancer patients. Changes in telomere length in mother-daughter pairs from breast cancer families and controls were also evaluated to address differences through generations. We demonstrated that short telomeres characterize hereditary but not sporadic breast cancer. We have defined a group of BRCAX families with short telomeres, suggesting that telomere maintenance genes might be susceptibility genes for breast cancer. Significantly, we described that progressive telomere shortening is associated with earlier onset of breast cancer in successive generations of affected families. Our results provide evidence that telomere shortening is associated with earlier age of cancer onset in successive generations, suggesting that it might be a mechanism of genetic anticipation in hereditary breast cancer.

Exploring the correlates of intermediate CAG repeats in Huntington disease.

Abstract: Objective: To explore the clinical phenotype in individuals with huntingtin gene CAG repeat lengths between 27 and 35, a range that is termed “intermediate” and below one traditionally considered diagnostic of Huntington disease (HD). Background: The Prospective Huntington Disease At-Risk Observational Study (PHAROS) found that patients with intermediate CAG lengths overlapped with those diagnosed as HD (≤ 37 CAG repeats) on the Unified Huntington's Disease Rating Scale (UHDRS) behavioral measures. Furthermore, several patients with intermediate CAG repeats demonstrating clinical (and pathological) evidence of HD have been reported. Methods: We reviewed all cases with intermediate CAG repeats who have presented to our clinic, as well as those reported in the literature. Results: We describe 4 patients with intermediate repeats evaluated at our center whose clinical features were highly suggestive of HD. Investigations for HD phenocopies were negative. Anticipation was demonstrated in 1 case with s...

Anticipation in hereditary disease: the history of a biomedical concept

Abstract: In the mid-nineteenth century, it was commonly believed that hereditary disease struck at the same time in succeeding generations, except for those cases in which it appeared at an earlier age. This exception to the rule was the precursor for the concept of anticipation in hereditary disease, a pattern of inheritance where a hereditary illness strikes earlier and often more severely in succeeding generations. Anticipation underwent cycles of acceptance and rejection over the course of the twentieth century and the ways in which this concept was received reveal complex interactions between science, medicine, and society.

Anticipation in lynch syndrome: where we are where we go.

Abstract: Lynch syndrome (LS) is the most common form of inherited predisposition to develop cancer mainly in the colon and endometrium but also in other organ sites. Germline mutations in DNA mismatch repair (MMR) gene cause the transmission of the syndrome in an autosomal dominant manner. The management of LS patients is complicated by the large variation in age at cancer diagnosis which requires these patients to be enrolled in surveillance protocol starting as early as in their second decade of life. Several environmental and genetic factors have been proposed to explain this phenotypic heterogeneity, but the molecular mechanisms remain unknown. Although the presence of genetic anticipation in Lynch syndrome has been suspected since 15 years, only recently the phenomenon has been increasingly reported to be present in different cancer genetic syndromes including LS. While the biological basis of earlier cancer onset in successive generations remains poorly known, recent findings point to telomere dynamics as a mechanism significantly contributing to genetic anticipation in Lynch syndrome and in other familial cancers. In this review, we summarize the clinical and molecular features of Lynch syndrome, with a particular focus on the latest studies that have investigated the molecular mechanisms of genetic anticipation.

Huntington’s Disease Pathogenesis: Mechanisms and Pathways

Abstract: The discovery in 1993 of the gene responsible for Huntington’s disease (HD) represented a crucial turning point in the HD research field. At the time of the discovery, no one could predict that HD would belong to a large class of inherited neurological diseases all caused by the same type of genetic mutation (i.e., polyglutamine [polyQ] expansion) or that the mechanistic basis of HD (i.e., protein misfolding) would emerge as a common theme linking together all the major neurodegenerative disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and the prion diseases. The study of how the mutant HD gene product, an unusually large 3,144 amino acid protein (huntingtin [htt]) with few recognizable motifs or obvious functional domains that results in the degeneration and death of neurons in the striatum and cortex, has been an enormous undertaking. Indeed, a PubMed search using the term “huntingtin” yields 1,124 hits at the time of writing this chapter. Suffice it to say that dozens of theories of pathogenesis have been proposed and studied. The goal of this chapter will be to present some of the most enduring lines of investigation, with an emphasis on the latest developments, and to highlight emerging notions likely to drive basic research on HD in the future.HD displays the genetic feature of anticipation, defined as earlier disease onset and more rapid disease progression in successive generations of a pedigree segregating the disease gene. This feature was an important clue for discovery of the causal mutation, as a trinucleotide repeat expansion encoding an elongated glutamine tract in the htt protein was determined to be responsible for HD in 1993, and a relationship between the length of the expanded glutamine tract and the severity of the HD phenotype was uncovered at that time [1]. HD is one of nine inherited neurodegenerative disorders caused by CAG trinucleotide repeats that expand to produce disease by encoding elongated polyQ tracts in their respective protein products. Included in this CAG/polyQ repeat disease class are spinal and bulbar muscular atrophy (SBMA), dentatorubral-pallidoluysian atrophy (DRPLA), and six forms of spinocerebellar ataxia (SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17) [2]. Based on work done on all these disorders, investigators have learned that once glutamine tracts exceed the mid-30s, the polyQ tract adopts a novel conformation that is pathogenic. An antipolyQ antibody (1C2) can specifically detect this structural transformation, as it will only bind to disease-length polyQ tracts from patients with different polyQ diseases [3]. The transition of polyQ-expanded proteins into this misfolded conformer is the crux of the molecular pathology in these disorders. Once in this conformation, however, it is unclear how polyQ tract expansions mediate the patterns of neuronal cell loss seen in each disease, as most of the polyQ disease gene products show overlapping patterns of expression within the central nervous system (CNS) but restricted pathology. In the case of HD, molecular explanations for disease pathogenesis must account for the selective vulnerability of the medium spiny neurons of the striatum and certain neuron subsets in the cortex.

Analysis of telomere dynamics in peripheral blood cells from patients with Lynch syndrome

Abstract: BACKGROUND: In patients with Lynch syndrome, germline mutations in DNA mismatch repair (MMR) genes cause a high risk of developing a broad spectrum of cancers. To date, the management of patients with Lynch syndrome has represented a major challenge because of large variations in age at cancer onset. Several factors, including genetic anticipation, have been proposed to explain this phenotypic heterogeneity, but the molecular mechanisms remain unknown. Telomere shortening is a common event in tumorigenesis and also has been observed in different familial cancers. In this study, the authors investigated the possibility of a relation between telomere length and cancer onset in patients with Lynch syndrome. METHODS: The mean telomere length was measured using quantitative polymerase chain reaction in peripheral blood samples from a control group of 50 individuals, from 31 unaffected mutation carriers, and from 43 affected patients, and the results were correlated with both gene mutation and cancer occurrence. In affected patients, telomere attrition was correlated with age at cancer onset. In all patients, a t test was used to assess the linearity of the regression. RESULTS: A significant correlation between telomere length and age was observed in both affected and unaffected mutation carriers (P = .0016 and P = .004, respectively) and in mutS homolog 2 (MSH2) mutation carriers (P = .0002) but not in mutL homolog 1 (MLH1) mutation carriers. Telomere attrition was correlated significantly with age at onset in MSH2 carriers (P = .004), whereas an opposite trend toward longer telomeres in patients with delayed onset was observed in MLH1 carriers. CONCLUSIONS: The current data suggested that telomere dynamics differ between MLH1 and MSH2 mutation carriers. It is possible that subtle, gene-specific mechanisms can be linked to cancer onset and anticipation in patients with Lynch syndrome. Cancer 2011;. © 2011 American Cancer Society.

Huntington's Disease

Abstract: Huntington’s disease (HD) is an autosomal dominant neurodegenerative brain disorder. The mutation was identified in 1993 as an expanded CAG repeat that codes for an abnormally high number of glutamines in the huntingtin protein. At present, there is no known treatment to slow the pace of neurodegeneration, which generally leads to death over a 20-year period after clinical diagnosis. The clinical manifestations of the disease vary widely but they generally include dysfunction in cognition, mood, voluntary motor control, and most patients have the signature finding of chorea.

Earlier age of onset in BRCA carriers-anticipation or cohort effect?: A Countercurrents Series.

Abstract: Is the age of onset of breast cancer in women with a BRCA1 or BRCA2 mutation decreasing? Two recent papers suggested that the effect of mutations is more profound with each successive generation 1,2. In a paper from Spain, the average age of breast cancer diagnosis declined by 6.8 years in BRCA1 carriers and by 12.1 years in BRCA2 carriers in one generation 1. In Texas, the median age of diagnosis declined by 6 years in a single generation, from 48 to 42 years 2. To be fair to others, the same phenomenon has been reported many times, dating back to 1993 3–10. What could be the cause of such an abrupt shift? Perhaps a deteriorating environment coupled with widespread inactivity among women? Perhaps women are being better screened? Or is the nature of the mutation changing? In each study, the authors reviewed the pedigrees of families with a BRCA mutation where women were affected both in the current (“proband”) generation and in the parental generation. The average age of diagnosis in each generation was calculated, compared, and found to be younger in the proband generation. But before examining those studies in detail, it is important to distinguish between genetic anticipation and a cohort effect. “Anticipation” refers to penetrance that increases with the number of generations elapsed since the mutation first arose de novo in a single individual. Anticipation was proposed for retinoblastoma (for which no molecular mechanism has been identified) in the 1970s 11, but better-known examples are Huntington disease 12 and myotonic dystrophy 13 (for which dynamic mutations in trinucleotide repeats underlie the shifts). It is important to note that, in anticipation, a decline in age at diagnosis is observed with subsequent generations within a pedigree, but the average age of diagnosis in the population shows no change with calendar time because each generation contains a mix of first-generation carriers, second-generation carriers, and so on. It is believed that, eventually, the age of onset becomes young enough that reproductive fitness is impaired, and the most harmful alleles are thereby lost in the population (and are replenished by de novo mutations). In a cohort effect, penetrance of the gene depends on the year of birth of the carriers. When a cohort effect is present, a decline in age at diagnosis with subsequent generations within a pedigree is also observed, but the average age at diagnosis in the underlying population is also observed to decline with calendar time, and the age-specific incidence rates are seen to increase with calendar time. Age-specific rates of cancer might also decline with age in a cross-sectional study. The groups from Spain and Texas both invoked anticipation as the likely mechanism for the observed declines in age of onset from generation to generation. But consider the most common BRCA1 mutation, 5382insC. This mutation has been estimated to have arisen some 70 generations ago somewhere in Eastern Europe 14. Does that provenance mean that the average age of diagnosis has been creeping down for each of 70 generations? Or only for the last one, like a dormant volcano that suddenly becomes active? Or is it the case that genetic anticipation acts on Houston mutations, but not on 5382insC mutations? Neither explanation will do. A cohort effect seems much more likely. Problems are inherent in both the Spanish and the Texas studies. Consider two hypothetical nuclear pedigrees: In each family, the mother is 75 and the daughter is 50. In the first family, the mother developed breast cancer at age 60, and the daughter developed breast cancer at age 40. In the second family, the mother developed breast cancer at age 40, and the daughter, healthy at 50, develops breast cancer 10 years later at age 60. In theory, these families should cancel each other out, but only the first family is eligible for the study. A woman in the first generation may have had breast cancer at any age up to 70, but a woman in the proband’s generation can only have early-onset breast cancer. Furthermore, it is critical to consider the criteria for genetic testing. If a young patient is more likely than an elderly patient to be tested, then the proband’s generation will be enriched for early-onset breast cancer. This analysis is pertinent for hospital clinics in which an early age of diagnosis is an explicit testing criterion. Lastly, the proband’s generation will include only bona fide carriers. The mother’s generation will include affected women who have not been tested and may include sporadic cases diagnosed, on average, at older ages. But better studies also support the idea of a cohort effect. One design that does not suffer from ascertainment bias involves studying a large and unselected series of breast cancer cases to identify the BRCA-positive subset, subsequently comparing the lifetime cancer risks in the sisters and mothers. If a cohort effect is present, then the lifetime risk of cancer should be greater in the sisters than in the mothers. Studies of this kind, with the results expected for a cohort effect, have been conducted by Gronwald et al. 8 in Poland and by King et al. 7 in the United States. The breast cancer risk by age 50 was estimated by King and colleagues to be 24% among mutation carriers born before 1940, but to be 67% among those born after 1940. Another approach is to show that the prevalence of BRCA1/2 mutations among incident cases of breast cancer increases with time 14. The assumption here is that the prevalence of mutations in the underlying population is fixed and that the risk of nonhereditary cancer does not change over the study period. In a prospective study of carriers in North America, we recently showed that the annual cancer rate was highest among women aged 25 to 40 years 15 (Table I). For young women, the annual risk reached an astonishing rate of 38% over a 10-year period—almost 4% per year. This effect may be age-related (that is, the cancer risk declines with age), but a cohort effect is also possible: that is, the risk for women born during 1935–1950 is about 1% per year throughout their lives, but the risk for women born during 1970–1985 is almost 4% per year. Either way, the enormous risks that young women with a mutation now face are a matter of concern. It is important that proper epidemiology studies be conducted so that the factors contributing to this risk—and to possible risk increase—can be identified. TABLE I Annual rates of breast cancer in carriers of BRCA1 mutations in North Americaa

Bayesian modeling for genetic anticipation in presence of mutational heterogeneity: a case study in Lynch syndrome.

Abstract: Summary Genetic anticipation, described by earlier age of onset (AOO) and more aggressive symptoms in successive generations, is a phenomenon noted in certain hereditary diseases Its extent may vary between families and/or between mutation subtypes known to be associated with the disease phenotype In this article, we posit a Bayesian approach to infer genetic anticipation under flexible random effects models for censored data that capture the effect of successive generations on AOO Primary interest lies in the random effects Misspecifying the distribution of random effects may result in incorrect inferential conclusions We compare the fit of four-candidate random effects distributions via Bayesian model fit diagnostics A related statistical issue here is isolating the confounding effect of changes in secular trends, screening, and medical practices that may affect time to disease detection across birth cohorts Using historic cancer registry data, we borrow from relative survival analysis methods to adjust for changes in age-specific incidence across birth cohorts Our motivating case study comes from a Danish cancer register of 124 families with mutations in mismatch repair (MMR) genes known to cause hereditary nonpolyposis colorectal cancer, also called Lynch syndrome (LS) We find evidence for a decrease in AOO between generations in this article Our model predicts family-level anticipation effects that are potentially useful in genetic counseling clinics for high-risk families

Genetics of the Autosomal Dominant Spinocerebellar Ataxias

Abstract: The spinocerebellar ataxias (SCAs) are a clinically, genetically and neuropathologically heterogeneous group of neurological disorders defined by variable degrees of cerebellar ataxia often accompanied by additional cerebellar and noncerebellar symptoms that, in many cases, defy differentiation based on clinical characterisation alone. The clinical symptoms are triggered by neurodegeneration of the cerebellum and its rely connections. Currently, there are 43 different genes associated with the autosomal dominant SCAs identified. Genetic studies refine the clinical diagnosis, provide molecular testing of at risk, a/presymptomatic, prenatal or preimplantation and facilitate genetic counselling in 27 SCA subtypes. Recent scientific advances are shedding light into the altered molecular pathways involved and the mechanisms by which the mutant gene products underlie neurodegeneration. This knowledge should be translated into effectively developing selective therapeutic strategies. The scope of this chapter is to provide an updated summary of the genetic aspects of the autosomal dominant SCAs. Key Concepts: Ataxia, a term that derives from the Greek, is a neurological disorder characterised by loss of control of voluntary body movements. Spinocerebellar ataxias, also known as SCAs, are a highly heterogeneous group of neurodegenerative diseases caused by cerebellar atrophy triggered by predominant loss of Purkinje cells in the cerebellum. The term ‘spinocerebellar ataxias’ is commonly used for those inherited progressive, congenital or episodic ataxias presenting an autosomal dominant inheritance. Mutations presenting incomplete penetrance in at least 43 genes are responsible for ataxia in the autosomal dominant SCAs. CAG repeat expansions encoding for polyglutamines in the gene products currently underlie neurodegeneration in seven spinocerebellar ataxia subtypes. Anticipation is a genetic phenomenon whereby the clinical symptoms become apparent at an earlier age as it is passed on to the next generation. This is associated with the germline transmission of an unstable expanded CAG-triplet repeat. Keywords: spinocerebellar ataxias; cerebellum; neurodegeneration; movement disorders; Purkinje cells; polyglutamine expansions; molecular diagnosis; genetic counselling; ataxia scales

Dentatorubral pallidoluysian atrophy.

Abstract: Publisher Summary This chapter provides an insight of the epidemiology, clinical features, imaging, genetics, pathology, diagnosis, and treatment of dentatorubral pallidoluysian atrophy (DRPLA). Most reported DRPLA cases are from Japan. DRPLA is a trinucleotide CAG repeat disorder caused by expansion of the CTG-B37 gene on chromosome 12p. The gene product, atrophin-1, is found throughout the body and the brain. Clinical heterogeneity is the rule in DRPLA. The six dominant clinical features of DRPLA are: ataxia, chorea, dementia/mental retardation, epilepsy, myoclonus, and psychiatric/behavioral symptoms. Pathologically, there is atrophy of the dentatorubral and pallidoluysian systems. As with other CAG repeat disorders, NIIs and diffuse polyglutamine expression are noted throughout the brain. DRPLA has the largest expansion and the most prominent anticipation among CAG repeat disorders, with earlier and more severe disease with paternal inheritance. DRPLA may be divided according to onset age: juvenile-onset types (

Clinical characteristics of Huntington disease in two pedigrees and analysis of expanded CAG trinucleotide repeat

Abstract: Objective To understand the clinical and genetic features of Huntington disease (HD). Methods The clinical data of HD cases from 2 Chinese families were analyzed and trinucleotide repeat in the IT15 gene were investigated in 9 of the two families by polymerase chain reaction and GeneScan. Results Among the two pedigrees, 6 cases were ascertained as HD by genetic test. Genotypes of IT15 were heterozygous in these HD patients. CAG repeat of the patients in the HD chromosome were 40-78. In the two pedigrees, the onset age was earlier in the subsequent generations than that of their fathers. In pedigree 2, the onset age was inversely correlated with CAG repeat number. One out of the 6 cases was juvenile-onset type of Huntington disease, whose clinical symptoms were different from those of the adult-onset cases, especially the hypertonic manifestation. Conclusion HD is an autosomal dominant neurodegenerative disorder with genetic anticipation caused by enlargement of CAG repeat in IT15 gene. The clinical manifestation is different between the juvenile-onset and the adult-onset. The number of CAG repeat is inversely correlated with the onset age and clinical severity.

Highlights of the 2010 North American Cystic Fibrosis Conference

Abstract: The 24th North American Cystic Fibrosis (CF) Conference was held in Baltimore, Maryland. The meeting did not have the heightened level of excitement of the past couple of years, but there was an air of anticipation relating to the number of ongoing trials of new therapies. In addition, novel therapies are emerging rapidly and it is clear that CF teams will need to reflect carefully on how these fit into their management strategies. The three plenary sessions are available on the CFF website:

Molecular diagnosis and treatment of two x-linked disorders.

Abstract: This issue contains two articles on X-linked genetic disorders. The first is a mini-review on a stereotypical X-linked disorder, Duchenne muscular dystrophy (DMD), and the second a comprehensive review on fragile X mental retardation (FXMR), a disorder which is also X-linked but which shows a more complex inheritance pattern and one which redefined our understanding of gene mutations. DMD is the most severe form of a number of disorders associated with deficiency of the muscle protein dystrophin, with Becker muscular dystrophy representing a milder form. Deficiency of dystrophin leads to muscle degeneration and replacement of muscle tissue with fat and connective tissues leading to progressive muscle weakness. It is a rapidly progressive form of muscular dystrophy affecting approximately one in every 3500 male births with the majority of patients being wheelchair bound by age 9–12 years. Most develop cardiomyopathy and pulmonary failure eventually leading to death.1 While most mutations are inherited, about one third occur spontaneously, that is, in the absence of any previous family history. In this issue Laing et al. review numerous aspects of the disorder with a particular emphasis on its molecular diagnosis and new approaches for its treatment including the use of morpholino antisense oligonucleotides to ‘skip’ past mutations or errors in the dystrophin gene. The article concludes with consideration of a call for population screening to maximise the benefits of such therapies. As forecast by a recent article by Pitt on newborn screening, screening for DMD may eventually occur, along with that of a number of other rare disorders not currently on newborn screening programs, particularly with the advent of increasingly affordable genetic tests.2 For the moment however, the issue of screening for DMD remains in dispute,3–5 particularly in the absence of an effective treatment. The gene therapies discussed by Laing hold promise, but there are a number of obstacles and we are at the very early phases of clinical trials, and time alone will tell if these can deliver on the promise. Like DMD, FXMR is also X-linked, but the inheritance pattern does not follow the classic Mendelian inheritance patterns expected of an X-linked disorder. In 1991, Isabelle Oberle and Jean-Louis Mandel’s team6 were among the pioneers in the molecular characterisation of the disorder, and almost 20 years after identification of the genetic locus for FXMR, one of the members of that team (Francois Rousseau) and his colleagues provide a comprehensive review of the genetic and molecular diagnostics aspects of this condition. Discovery of the genetic defects in FXMR was important from several points of view. It has greatly facilitated diagnosis of a common cause of mental retardation, but it also expanded our understanding of genetic variation, genetic anticipation and DNA stability and introduced new terms such as ‘dynamic mutations’, ‘premutation’ and ‘abnormal methylation’ to the genetic lexicon. ‘Anticipation’ refers to the worsening of symptoms with each generation and ‘dynamic’ to the change in the severity of the mutation at the DNA level, from a so-called premutation to a full mutation. The FXMR story also shed light on the molecular mechanisms that lead to genetic imprinting. FXMR is due to mutation of the FMR1 gene, most often due to an expansion of the number of repeats of the CGG-rich triplet sequence in the first exon of the gene, which encodes the protein FMRP. Although genes often have repeats as part of their sequence, when the number of repeats becomes too large, it can lead to disease. In this case, the expansion from a premutation (greater than the ‘normal’ number of repeats but not sufficient to cause disease) into a full mutation leads to increased methylation of the gene which in turn decreases its ability to be transcribed to mRNA, effectively silencing the gene. Fragile X was the first of the so-called triplet repeat diseases to be discovered. Others in this category include Huntington’s disease and myotonic dystrophy. To decipher the molecular and population genetics of FXMR mutations, researchers around the world had to undertake very large studies involving tens of thousands of individuals. The product of the FMR1 gene, FMRP has interesting properties, as it is involved, for instance, in post-transcriptional control of mRNA expression. The review is long, and at times complex, but it holds many lessons including diagnostic challenges and the role of the gene in predisposing to other disorders including premature ovarian failure.

Organic acid, amino acids, and peroxisomal disorders

Abstract: The dentato-rubro-pallido-luysian atrophy (DRPLA) disorder was predominantly seen in the Japanese population. DRPLA is an autosomal dominant neurodegenerative disorder caused by abnormal repeat expansions within the DRPLA gene located on chromosome 12p13.31. Ataxia, choreoathetosis, and/or myoclonus and mental decline are the cardinal signs. Epileptic seizures usually occur in patients with an earlier onset. Unstable expanded CAG repeats in one allele in the DRPLA gene are responsible for this disorder and the size of the CAG expansion is well correlated with age of onset and severity of the disease. There are characteristic degeneration of both the dentato-rubral and pallido-luysian systems in the brain. Diffferential diagnosis includes all types of progressive myoclonic epilepsies, hereditary ataxia, and Huntington chorea. An autosomal dominant hereditary pattern and anticipation from the paternal side make the diagnosis more likely. However, a definitive diagnosis is based on genetic testing.

Letter to the editor. Re: C-reactive protein is superior to bilirubin for anticipation of perforation in acute appendicitis.

Abstract: TO THE EDITOR: We read with interest the work by Käser et al. [1] as any research that helps with the diagnosis of the age old problem of differentiating between a perforated and non-perforated appendix is extremely useful, especially in the emergency department setting. We are currently undertaking a study retrospectively investigating ~1300 appendicectomy patients and trying to ascertain the use of measuring CRP, bilirubin and white blood cells in predicting an appendix perforation. So far we have produced a preliminary data set that has analyzed the results from 230 patients, 25 of whom had a perforation (group A) and 205 did not (group B). Bilirubin levels were available for 23/25 and 164/205 patients in group A and B, respectively. Similarly, CRP levels were available for only 22/25 patients in group A and all patients in group B. We have also found that CRP and bilirubin are raised in patients with a perforation by a statistically significant amount and that white blood cell levels are no different between the groups. When investigating the positive and negative predictive values and the sensitivity and specificity, we have found that using one of these results alone is not appropriate. The sensitivity of a raised bilirubin level for detecting a perforated appendix was 0.4, with the specificity being 0.81. For CRP, the sensitivity was 0.96, but the specificity was 0.38. The positive predictive values of bilirubin and CRP were 70.8% and 84%, respectively, while the negative predictive values were 92.2% for normal bilirubin levels and 75.9% for normal CRP levels. Therefore, we suggest that the results of the highquality research from Käser et al. are read with careful consideration by a clinician. There is a need to utilize both the CRP and the bilirubin results to provide a more accurate indication of the potential of a perforated appendix. Simply relying on a raised CRP level is not sufficient due to the low specificity of this test and the negative predictive value of a normal bilirubin result.